Share this story

The test conductor (TC) seemed to delight in telling me that I just committed a fatal spacewalking error (there are many to choose from). Her clever comments weren’t needed to teach me the importance of proper tethering. The life-saving handrail retreating from my outstretched glove was obvious enough. In space, my transgression could have sent me into an irreversible trajectory away from the International Space Station (ISS), rendering me just another piece of space junk adrift in low-Earth orbit.

Behind the scenes

This, however, was an exercise at NASA’s pool used for spacewalk training, the Neutral Buoyancy Laboratory (NBL) in Houston. I'd hear similar admonitions at least twice more during the day, as SCUBA divers hovered close by to keep my free-floating tendencies (and my future as a meteor) in check.

My day at the pool was one of the highly coveted opportunities for non-astronaut “test subjects” to don a spacesuit (NASA calls it the EMU—Extravehicular Mobility Unit) and experience first-hand some of the peculiarities of working in space. While this insight is valuable to the engineers who deal with the EMU and space tools, that wasn't the point of this event. My function was to periodically play the role of a distressed and unconscious astronaut for the benefit of the divers who are tasked with rescuing such unfortunate souls during “real” training events.

I suppose that being given the opportunity to put on an EMU could lead one to feel a twinge of self importance. The suit, however, has a way of metering such delusions of grandeur with heaping doses of humility. In fact, the first step of the sizing process involves standing before a full-mirrored wall in government-issue skivvies while a team of caliper-toting technicians measures your every dimension. Then comes the moment when you actually have to get into the EMU, the upper part of which is completely rigid. Imagine forcing your way into an extremely overstarched shirt… while it remains buttoned and hanging in the closet. Success requires equal parts contortionism and masochism.

For many, their first minute in the EMU is a defining moment. You’re either going to be good with it, or you’re going to be clawing rabidly to get out rightnow! It’s not that the suit isn’t comfortable once you’re fully buttoned up, it’s just rather confining. If you get antsy during an MRI, just go ahead and shred your astronaut application form now. There’s no room for your claustrophobia in the EMU.

In the often cryptic acronym-based NASA lingo, astronauts do not perform spacewalks. Instead, they “go EVA” (extravehicular activity). As astronauts invariably go EVA with a partner, so goes the NBL. My plus-one in this venture was Robert Knight, a fellow engineer with four previous gigs in the pool. We agreed to an ambitious set of tasks that would test our presumed EVA skills, with some obligatory faux fainting spells that would challenge our acting chops. Perhaps even ersatz astronauts are competitive by nature.

Test subjects and astronauts alike are bound to an unwritten yet rarely broken NBL commandment: “thou shalt feed the staff.” Donuts and kolaches are staples of the morning menu. When astronaut Nicole Stott is at the pool, you have to act fast to nab one of her homemade cookies. Robert and I splurged on a heavy stash of breakfast burritos that we hoped would satiate the divers and spare us some of the good-natured hazing that is due all test subjects (and most astronauts).

As I prepare for my training event, engineers and technicians install an array of tools that I'll use throughout the day. Note the multiple tether hooks attached near my chest that would soon torment me.

NASA

Following breakfast and a smattering of preliminary tasks, a crane lowered us into the water. Here the enormous full-scale mockup of the ISS came in to clear view. Sure, 6.2 million gallons sounds like a big pool, but it’s impossible to comprehend its true vastness until you pierce the surface and take in all three dimensions (202’ × 102’ × 40’). I had to limit my gawking due to the extreme fisheye effect that the EMU helmet creates in water. This distortion doesn’t manifest itself in space or air, but it can be very disorienting and nauseating in the pool. I focused intently on the tools stowed just below my helmet until my eyes could adjust.

My three support divers took me down 40 feet to the pool floor. They placed foam and/or weights in various pockets of the EMU to make it neutrally buoyant in order to emulate the weightlessness of space. In open water, Robert and I were completely dependent on the divers for mobility (this is where the breakfast investment pays off). They spun and twirled us into countless orientations while fine-tuning our buoyancy.

By this time, my eyes were well adjusted and I was enjoying myself immensely. It was like a slow-motion roller coaster ride with a magnificent view. I especially liked being placed on my back. I was able to see a panoramic perspective of the ISS mockup slightly above and all around me. I watched the diver’s bubbles race toward the ceiling lights that were randomly skewed by the choppy surface of the pool. This Dali-esque scene felt very surreal and I never tired of it. Unfortunately, Robert was not faring quite as well. On this day, his eyes refused to adjust to the helmet-altered visual perspective. He wisely conceded defeat to the onrushing nausea and was removed from the pool.

You're wearing what's called a MAG—a "Maximum Absorbancy Garment". It's a highly absorbent device that is configured to enable astronauts to eliminate waste efficiently and without interfering with mission goals and objectives.

You're wearing what's called a MAG—a "Maximum Absorbancy Garment". It's a highly absorbent device that is configured to enable astronauts to eliminate waste efficiently and without interfering with mission goals and objectives.

You have to consider two things from an engineering standpoint though. 1: It would cost too much money for everyone to have a custom spacesuit. Only the gloves are custom built. So you have to make the suit usable for various sized people. I think NASA's height limit is 5'1 to 6'2 for example. 2: A spacesuit is basically a self contained spacecraft. So you need to account for all the things you need.for such a suit like life support, water bag, communications, etc. Plus a more skin tight spacesuit would be harder to make. Since you need to have constant pressure all throughout the suit.

Having read a fair number of accounts of EVAs and people doing practice it does seem like there are definite places for improvement with the current suits. Some sort of motor assist on the gloves for instance to make gripping things less of a chore. A flat plate on the front of the visor to avoid distorting the view so much. Maybe even a complete redesign of the suit. Maybe not even have the suits (or not use them much) and instead develop smaller probes with Waldo arms and POV cameras--you could even have multiple operators to help share the cognitive load. The advantage of having a real person out there seems to be somewhat lost when they're so compromised by the rigors of just wearing the suit in the first place.

It won't be easy, things are built the way they are for a reason now and proving a new technology in space is a big challenge. However, the current solution feels like a stopgap that has persisted for far too long.

A flat plate on the front of the visor to avoid distorting the view so much.

The view isn't distorted when you're in a real space suit in space. It's the index of refraction change between air and water that causes the distortion, so it only happens underwater. That said, for sure there are several ongoing efforts for developing better future space suits, and better gloves are one of the top targets.

And conversely there is a TON of robotics development, including a major NASA project office at Goddard working on systems for fully robotic repair and servicing of spacecraft. Harder than it sounds because of the communication delays - even when light travel time isn't a major factor, the network overhead from routing through the various ground systems up through TDRSS means that the network lag is pretty brutal to the ISS or any future robotic servicing work platform. So you have to do a lot of local autonomy and not just pure teleoperation, which they're developing and demoing right now on the ISS with the Robotic Refueling Mission payload.

*Jealous much*too bad am too old now for the commercialized MARS ONE astronaut thing. Since my childhood I've regularly felt I'm 100/0 years too early born and feel more "home" out there in space. I've always been the exploratory type of person.It wasn't easy for me to realize, that the ship has sailed for me in that regards, and to give way for the generation after me.Anyhoo - kudos for a well 'visualized' article

Sometimes I wonder why NASA doesn't recruit a few unusually bright construction workers. Find someone who's been working out of a 60 meter boom lift for a while. One thing they won't do is mess up a safety line by turning the wrong way Nothing teaches you like being 10 stories up and too fouled to work.

For real giggles, maybe someone who works at heights up north. 20 kg of trying not to freeze, fall protection gear, "don't drop your hammer" lines all over the place, multiple lights that always seem to make things worse, and trying to fit a screw into a hole wearing gloves that keep you from losing fingers at -40.

Astronauts have it harder. But they could eliminate a lot of the learning curve for people who are, in essence, really unusual construction workers.

IIRC, that's the plot (or at least the initial hook) of Moonlight Mile.

A lot of the maneuverability and manipulation problems would be solved by further development of the Space Activity Suit (AKa those skin-tight sci-fi spacesuits), using mechanical counterpressure rather than a sealed and pressurised sort-of-man-shaped balloon. Evaporative cooling by letting sweat filter through the garment is ingenious, and being able to operate just the helmet at 1ATM (or whatever pressure and mix you hold your spacecraft or spacestation at) means no pre-breathing. Getting in and out of them would be even trickier than a 'normal' spacesuit unless you could produce fabrics with controllably variable elasticity, but there have been proposals to use mechanical counterpressure purely for gauntlets attached to a regular pressurised spacesuit.

I know the idea is to make the EMU in underwater training as close to the spacesuit version, but it does seem like it would make sense to make modifications to the underwater one so that it gives the wearer more of a similar experience, rather than the same outward appearance. So a flattened window on the visor would seem completely appropriate.

Use a pool of [url]http://en.wikipedia.org/wiki/Chlorodifluoromethane]R-22[/url] (cooled to at least -47C, the divers might need another centimeter of neoprene)

1.26 refractive index. a whole 0.1 improvement over water!

It's about 41% denser than water at the temperature, so you'd need a bit more weight ballast too.

Plus wikipedia says that the EPA indicated there was a minimum inventory of 22.7K metric tonnes, which I calculate to be about 16 million liters it in liquid form, given that the mock-up ISS must displace quite a bit that sounds just about right.

Don't think you'd get so many volunteers queuing up to go EVA testing in it though

A flat plate on the front of the visor to avoid distorting the view so much

Others have mentioned that the view distortion is mostly lessened when in space, but I'd hazard there's also a structural reason for a spherical helmet.

In a sphere, the pressure at any point on the surface is equal with every other point. This isn't the case in a shape with flat sides, which necessarily is going to have corners somewhere. The corners are going to create all kinds of stress profiles, which makes the designing of a space helmet much more complicated. It wouldn't surprise me if you'd need a much thicker "glass" (for lack of a better term) if you wanted a flat visor vs the current spherical ones.

A flat plate on the front of the visor to avoid distorting the view so much

Others have mentioned that the view distortion is mostly lessened when in space, but I'd hazard there's also a structural reason for a spherical helmet.

In a sphere, the pressure at any point on the surface is equal with every other point. This isn't the case in a shape with flat sides, which necessarily is going to have corners somewhere. The corners are going to create all kinds of stress profiles, which makes the designing of a space helmet much more complicated. It wouldn't surprise me if you'd need a much thicker "glass" (for lack of a better term) if you wanted a flat visor vs the current spherical ones.

well since the pressures even at the bottom of 40 ft of water aren't that great, i wonder whether they have ever experimented with flat glass/plastic helmet lenses just for use in the pool? that would hopefully eliminate the fish-eye shrinking of stuff, maybe making training easier.

Thanks for all of the positive comments everyone. I definitely appreciate it.

As for the visor debate, I'm sure that the fisheye effect could be cured without too much fuss. However, it really isn't an issue for the day to day activities in the pool. The normal work envelope for an astronaut in training is so limited that the distortion is easily ignored by most people. It's just when greenhorns like myself want to soak in panoramic views that things get psychedelic. Furthermore, the helmet/visor is a really tight fit and requires developed techniques even for actions like turning your head without snagging the microphone boom. Anything other than a flight-like helmet would probably cause negative training in that regard. Lastly, the training EMUs are pretty much identical to flight versions. In fact, many NBL EMU components are former spaceflight veterans. When we're talking life-sustaining pressure vessels, nothing is cheap. So, it makes sense to maintain as much commonality as possible between flight and training inventories.

This is a really interesting article and it is the kind of thing that makes Ars stand out from the crowd. I just hope that the number of comments does not reflect the readership figures. The NBL is something to add to my "it would be cool to do, but I will never get the chance" list.

You're wearing what's called a MAG—a "Maximum Absorbancy Garment". It's a highly absorbent device that is configured to enable astronauts to eliminate waste efficiently and without interfering with mission goals and objectives.

You're wearing what's called a MAG—a "Maximum Absorbancy Garment". It's a highly absorbent device that is configured to enable astronauts to eliminate waste efficiently and without interfering with mission goals and objectives.

You're wearing what's called a MAG—a "Maximum Absorbancy Garment". It's a highly absorbent device that is configured to enable astronauts to eliminate waste efficiently and without interfering with mission goals and objectives.